python制作websocket服务器实例分享

一、开始的话

　　使用python简单的实现websocket服务器，可以在浏览器上实时显示远程服务器的日志信息。

　　之前做了一个web版的发布系统，但没实现在线看日志，每次发布版本后，都需要登录到服务器上查看日志，非常麻烦，为了偷懒，能在页面点几下按钮完成工作，这几天查找了这方面的资料，实现了这个功能，瞬间觉的看日志什么的，太方便了，以后也可以给开发们查日志，再也不用麻烦运维了，废话少说，先看效果吧。

二、代码

　　需求：在web上弹出iframe层来实时显示远程服务器的日志，点击stop按钮，停止日志输出，以便查看相关日志，点start按钮，继续输出日志，点close按钮，关闭iframe层。

　　在实现这功能前，google了一些资料，发现很多只能在web上显示本地的日志，不能看远程服务器的日志，能看远程日志的是引用了其他框架（例如bottle，tornado）来实现的，而且所有这些都是要重写thread的run方法来实现的，由于本人技术太菜，不知道怎么改成自己需要的样子，而且我是用django这个web框架的，不想引入其他框架，搞的太复杂，所以用python简单的实现websocket服务器。recv_data方法和send_data是直接引用别人的代码。由于技术问题，代码有点粗糙，不过能实现功能就行，先将就着用吧。

执行下面命令启动django和websocketserver

nohup python manage.py runserver 10.1.12.110 &
nohup python websocketserver.py &

　　启动websocket后，接收到请求，起一个线程和客户端握手，然后根据客户端发送的ip和type，去数据库查找对应的日志路径，用paramiko模块ssh登录到远程服务器上tail查看日志，再推送给浏览器，服务端完整代码如下：

# coding:utf-8
import os
import struct
import base64
import hashlib
import socket
import threading
import paramiko


def get_ssh(ip, user, pwd):
  try:
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(ip, 22, user, pwd, timeout=15)
    return ssh
  except Exception, e:
    print e
    return "False"


def recv_data(conn):  # 服务器解析浏览器发送的信息
  try:
    all_data = conn.recv(1024)
    if not len(all_data):
      return False
  except:
    pass
  else:
    code_len = ord(all_data[1]) & 127
    if code_len == 126:
      masks = all_data[4:8]
      data = all_data[8:]
    elif code_len == 127:
      masks = all_data[10:14]
      data = all_data[14:]
    else:
      masks = all_data[2:6]
      data = all_data[6:]
    raw_str = ""
    i = 0
    for d in data:
      raw_str += chr(ord(d) ^ ord(masks[i % 4]))
      i += 1
    return raw_str


def send_data(conn, data):  # 服务器处理发送给浏览器的信息
  if data:
    data = str(data)
  else:
    return False
  token = "x81"
  length = len(data)
  if length < 126:
    token += struct.pack("B", length)  # struct为Python中处理二进制数的模块，二进制流为C，或网络流的形式。
  elif length <= 0xFFFF:
    token += struct.pack("!BH", 126, length)
  else:
    token += struct.pack("!BQ", 127, length)
  data = '%s%s' % (token, data)
  conn.send(data)
  return True


def handshake(conn, address, thread_name):
  headers = {}
  shake = conn.recv(1024)
  if not len(shake):
    return False

  print ('%s : Socket start handshaken with %s:%s' % (thread_name, address[0], address[1]))
  header, data = shake.split('rnrn', 1)
  for line in header.split('rn')[1:]:
    key, value = line.split(': ', 1)
    headers[key] = value

  if 'Sec-WebSocket-Key' not in headers:
    print ('%s : This socket is not websocket, client close.' % thread_name)
    conn.close()
    return False

  MAGIC_STRING = '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
  HANDSHAKE_STRING = "HTTP/1.1 101 Switching Protocolsrn" 
            "Upgrade:websocketrn" 
            "Connection: Upgradern" 
            "Sec-WebSocket-Accept: {1}rn" 
            "WebSocket-Origin: {2}rn" 
            "WebSocket-Location: ws://{3}/rnrn"

  sec_key = headers['Sec-WebSocket-Key']
  res_key = base64.b64encode(hashlib.sha1(sec_key + MAGIC_STRING).digest())
  str_handshake = HANDSHAKE_STRING.replace('{1}', res_key).replace('{2}', headers['Origin']).replace('{3}', headers['Host'])
  conn.send(str_handshake)
  print ('%s : Socket handshaken with %s:%s success' % (thread_name, address[0], address[1]))
  print 'Start transmitting data...'
  print '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -'
  return True


def dojob(conn, address, thread_name):
  handshake(conn, address, thread_name)   # 握手
  conn.setblocking(0)            # 设置socket为非阻塞

  ssh = get_ssh('192.168.1.1', 'root', '123456')  # 连接远程服务器
  ssh_t = ssh.get_transport()
  chan = ssh_t.open_session()
  chan.setblocking(0)  # 设置非阻塞
  chan.exec_command('tail -f /var/log/messages')

  while True:
    clientdata = recv_data(conn)
    if clientdata is not None and 'quit' in clientdata:  # 但浏览器点击stop按钮或close按钮时，断开连接
      print ('%s : Socket close with %s:%s' % (thread_name, address[0], address[1]))
      send_data(conn, 'close connect')
      conn.close()
      break
    while True:
      while chan.recv_ready():
        clientdata1 = recv_data(conn)
        if clientdata1 is not None and 'quit' in clientdata1:
          print ('%s : Socket close with %s:%s' % (thread_name, address[0], address[1]))
          send_data(conn, 'close connect')
          conn.close()
          break
        log_msg = chan.recv(10000).strip()  # 接收日志信息
        print log_msg
        send_data(conn, log_msg)
      if chan.exit_status_ready():
        break
      clientdata2 = recv_data(conn)
      if clientdata2 is not None and 'quit' in clientdata2:
        print ('%s : Socket close with %s:%s' % (thread_name, address[0], address[1]))
        send_data(conn, 'close connect')
        conn.close()
        break
    break


def ws_service():

  index = 1
  sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  sock.bind(("127.0.0.1", 12345))
  sock.listen(100)

  print ('rnrnWebsocket server start, wait for connect!')
  print '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -'
  while True:
    connection, address = sock.accept()
    thread_name = 'thread_%s' % index
    print ('%s : Connection from %s:%s' % (thread_name, address[0], address[1]))
    t = threading.Thread(target=dojob, args=(connection, address, thread_name))
    t.start()
    index += 1


ws_service()

get_ssh的代码如下：

import paramiko
def get_ssh(ip, user, pwd):
  try:
    ssh = paramiko.SSHClient()
    ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
    ssh.connect(ip, 22, user, pwd, timeout=15)
    return ssh
  except Exception, e:
    print e
    return "False"

打开页面时，自动连接websocket服务器，完成握手，并发送ip和type给服务端，所以可以看不同类型，不同机器上的日志，

页面代码如下:

<!DOCTYPE html>
<html>
<head>
  <title>WebSocket</title>

  <style>
  #log {
    width: 440px;
    height: 200px;
    border: 1px solid #7F9DB9;
    overflow: auto;
  }
  pre {
    margin: 0 0 0;
    padding: 0;
    border: hidden;
    background-color: #0c0c0c;
    color: #00ff00;
  }
  #btns {
    text-align: right;
  }
  </style>

  <script>
    var socket;
    function init() {
      var host = "ws://127.0.0.1:12345/";

      try {
        socket = new WebSocket(host);
        socket.onopen = function () {
          log('Connected');
        };
        socket.onmessage = function (msg) {
          log(msg.data);
          var obje = document.getElementById("log");  //日志过多时清屏
          var textlength = obje.scrollHeight;
          if (textlength > 10000) {
            obje.innerHTML = '';
          }
        };
        socket.onclose = function () {
          log("Lose Connection!");
          $("#start").attr('disabled', false);
          $("#stop").attr('disabled', true);
        };
        $("#start").attr('disabled', true);
        $("#stop").attr('disabled', false);
      }
      catch (ex) {
        log(ex);
      }
    }
    window.onbeforeunload = function () {
      try {
        socket.send('quit');
        socket.close();
        socket = null;
      }
      catch (ex) {
        log(ex);
      }
    };
    function log(msg) {
      var obje = document.getElementById("log");
      obje.innerHTML += '<pre><code>' + msg + '</code></pre>';
      obje.scrollTop = obje.scrollHeight;  //滚动条显示最新数据
    }
    function stop() {
      try {
        log('Close connection!');
        socket.send('quit');
        socket.close();
        socket = null;
        $("#start").attr('disabled', false);
        $("#stop").attr('disabled', true);
      }
      catch (ex) {
        log(ex);
      }
    }
    function closelayer() {
      try {
        log('Close connection!');
        socket.send('quit');
        socket.close();
        socket = null;
      }
      catch (ex) {
        log(ex);
      }
      var index = parent.layer.getFrameIndex(window.name); //先得到当前iframe层的索引
      parent.layer.close(index); //再执行关闭
    }
  </script>

</head>


<body onload="init()">
  <div >
    <div >
      <div id="log" ></div>
      <br>
    </div>
  </div>
  <div >
    <div >
      <div id="btns">
        <input disabled="disabled" type="button" value="start" id="start" onclick="init()">
        <input disabled="disabled" type="button" value="stop" id="stop" onclick="stop()" >
        <input type="button" value="close" id="close" onclick="closelayer()" >
      </div>
    </div>
  </div>
</body>

</html>

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